Spent the summer with HTC one and Momentum. I think it really is a nice portable rig, but feel the HTC One needs to have some volume to make the Momentum shine. On my desktop amps, I do not feel the Momentum needs volume to shine. I really thought the Momentums were good on my iPod Classic and the iPhone4 - on lower volume I found it better on lower volumes. The iStuff seems brighter, and brings some sparkle to the Momentum..

Think its a match made in heaven. The 4Rs really sound an awful lot better than compared to my latest Ipod Touch. I never used an amp, since its too tough to buy them here in my country. But SQ wise the 4Rs are brilliant,One + Poweramp.+ FLAC=